Apparatus for rotary drilling of wells using casing as drill pipe

ABSTRACT

A drilling system employing casing as drill pipe and a bit section which is bodily insertable and removable through the casing and releasably attachable thereto for rotation with the casing.

United States Patent Inventor Cicero C. Brown c/o Brown Oil Tools, Inc. P.O. Box 19236, Houston, Tex. 77024 Appl. No. 857,046 Filed Sept. 11, 1969 Patented Jan. 5, 1971 APPARATUS FOR ROTARY DRILLING OF WELLS USING CASING AS DRILL PIPE 11 Claims, 6 Drawing Figs.

U.S. Cl 175/258, 175/267 Int. Cl. 1521b 9/26 Field of Search 175/257,

References Cited UNITED STATES PATENTS Sewell Brown Goodwin Kammerer...

Kammerer... Kammerer Primary Examiner-David H. Brown Attorney-R. Werlin 175/258 175/258 l75/267X l75/267X 175/258 175/267X ABSTRACT: A drilling system employing casing as drill pipe and a bit section which is bodily insertable and removable through the casing and releasably attachable thereto for rotation with the casing.

PATENTEUJANSIBII 35521509 SHEET1UF4 A T TORNEYS W EICERO G 50 N PATENTEU JAN 5.19m

SHEEF 2 OF 4 PATENTED JAN 5 I971 SHEET 3 0P4 A T TOPNE) PATENTEDJAN Sign saw u or 4 ow/v a/cERO a 55 A TTORNEY APPARATUS FOR ROTARY DRILLING or WELLS USING CASING AS DRILL PIPE 1 RELATED APPLICATIONS This application is related-to my copending application Ser. No. 803,91 1 filed Mar. 3, 1969. In the drilling of wells for oil and gas, for example, by the rotary method, the drilling is conventionally done by the emof sections to the drill pipe, and also the entire drill string must be withdrawn whenever it becomes necessary to replace the bit and then reinsert it to resume drilling. Thus making of such so-called "round trips" are not only time consuming but also create hazards of blowouts and other undesirable conditions in the well. After the appropriate drilling of the hole has been completed, the drill string must be withdrawn and easing run to the desired depth. This, too, may present hazards because with the drill string out of the well, control of the well becomes Heretofore numerous efforts have been'made to provide a system employing the'casing itself as the'drillpipe in order to overcome some'of the hazards enumerate'dQjas well as time loss. However, these prior efforts-havenotproven satisfactory forvarious reasons well knownto those skilledin the an.

The present invention, therefore, is directed to an improved arrangement by which the casing may beemployed as the drilling string and when used in combinationwith a retractable or removable bit section will perform all of the functions of drilling and casing of a well in a sequenceor'series of operations which thereby greatly facilitates drilling operations.

In accordance with the present invention-a bit section is provided which includes both the primary bit and aplur ality of radially extendible and retractable underrearners, the entire bit section being-arranged and constructed to be insertable bodily through the bore of the casing and moved to the lower end of the casing either on a wire line or by simplydropping it into the casing, where, either'by gravity alone or supplemented by pumped fluid pressure, the bit section will be forced to the bottom of the lower end of .the casing string, which is provided with a landing shoe to receivethe bit section. The bit section is-provided with latch means engageable' withappropriate grooves or other latch-receiving structure. in the landing shoe. The latter includes a number of keys or splines which are adapted to engage appropriate spline slots or grooves in the bit section to lockth'e bit section to the casing against relative rotation whereby rotation of the casing string will be effective to rotate the bit forpurposes of drilling the the bore hole, the body of the bit section isprovided with a plurality of angularly spaced jet nozzles a short v substantially increase the overall cutting speed of the bit section.

Additional jet sprays are provided through the bit body directed to strike against the undcrreamers whereby to wash cuttings from between the underreamer teeth to continuously clean the teeth and further improve the cutting efficiency of the undcrreamers.

The undcrreamers as herein disclosed incorporate yet a further improvement in the provision of an arrangement for effecting self-lubrication of the underreamer bearings by application of the pressure of the drilling fluid from the interior of the bit body to'a body of a suitable lubricant enclosed within the hollow underreamer shafts whereby the lubricant is forced into clearance spaces about the several bearings arranged between the underreamer cutters and the shafts.

To withdraw the bit section a conventional fishing tool or spear is run into the casing on a wire line and connected to the bit section, whereby an upward pull applied to the fishing tool will be effective to retract the undcrreamers and release the bit section from the landing shoe to which it has been anchored. 5

Other and more specific objects and advantages of this in-' vention will become more readily apparent from the following detailed description when read in conjunction with the accompanying drawing which illustrates a useful embodiment in accordance with the present invention.

IN THE DRAWING FlG. 1 is a longitudinal, partly sectional view showing the bit section inserted into the casing shoe preparatory to anchoring the bit section to the casing shoe;

FIG. 2 is aview similar to'FlG. 1' showing the bit section anchored to the casing shoe and with the undcrreamers in their extended position;

H0. 3 is a view similar to FIG. 1 showinga fishing tool engaged with the bit section, the parts being-shown after release of the bit section and with the underreamers'in'their retracted bore showing the casingstiing with the bit section in place and the drive connections at the surface;-

F lG. 5 is'a cross-sectional view taken along line 5--5 of FIG. 2; and t FIG. 6 is a detail, in section, taken along line 6-6 of F1652;

Referring to the drawing and considering first FIG. 4, there is shown a string of easing C carrying the bit section, designated generally by the'letter'B, showing the bit section in placein a landing shoe lo connected to the lower end of casing C. At its upper end casing C is connected to a power sub P which functions to rotate the casing string during drilling, as will be described. Powersub P is of the general form and construction disclosed in lily copending application Ser." No. 736,179, filed now US. Pat. No.,.3,467,202, filed Jun. 1 1, I968. Asuitable drive connection between the power sub and the casing is disclosed inmy copending applicatiori'Ser. No. 778,509, filed Nov. 2 5, 1968. Power sub? is suspended from a swivel 8 carried onelevators E conventionally employed as part of the idr-awworks-of a drilling rig. The swivel has'a hose connection by which drilling mud is pumped into the drill ,string of casing C, thencethrough'the bit section into the an- '65 To supplement the action of the undcrreamers in enlarging distance below the undcrreamers (in their extended posit-ions) I andarranged to produce highvelocity, high pressure radiallyv directed jets of the drilling fluid against the bfore wall formed vided-with two or more angularly spaced pins l4-which project a short distance inwardly of the bore of the shoe and form splines for purposes which willbe explained shortly.

Bitsection B comprises a body, 16 having a generally cylindrical bore 17, and is dimensioned to he inscrtable through the bore of easing C and into the bore of shoe [0. Body 16 is provided about an intermediate portion thereof with a plurality of longitudinal keyways or spline grooves 18 open at their lower ends and adapted to receive the inwardly projecting ends of the pins 14, whereby body 16 will be locked to shoe 10 against relative rotation so that rotation of easing C will function to rotate body 16 and its appurtenances. Spline grooves 18 terminate in upper end walls 19 which form stops for engagement with pins 14 to limit downward movement of the bit body through shoe 10. An annular seal ring 20 is disposed about the exterior of body 16 above end wall 19 to seal with the bore wall of shoe 10. At a point above seal 20, body 16 is provided with a plurality of radial windows or openings 22 of generally rectangular shape in which are mounted latch dogs 24 which are adapted when projected outwardly to be received in an annular latching groove 26 formed in bore wall 15 of shoe 10. The latching dogs are positioned in body 16 so that they will be in registration with groove 26 when body 16 is fully inserted in the shoe with spline end walls 19 abutting pins 14. The upper end of body 16 is internally threaded to define the box or socket 28 adapted to threadedly receive a collar 30 having a downwardly facing internal shoulder 32 spaced a short distance below its upper end. The lower end of body 16 carries a downwardly facing internally threaded socket 34 adapted to receive the externally threaded shank 36 of a bit 38 which constitutes the pilot bit and may be of any conventional design for drilling a bore hole to any desired nominal diameter determined by the dimensions of the pilot bit.

At a point between the lower ends of splines 18 and socket 34, body 16 is provided with a plurality of longitudinally extending radially opening slots 40 in which are mounted underreamers, designated generally by the numerals 42. These are pivotally mounted on pivot pins 46 which extend transversely of the respective slots 40 for enabling the underreamers to be angularly moved so as to be radially projected and retracted with respect to the slots 40.

Each of the underreamers 42 comprises a tubular shaft 43, having an axial bore 44, and secured at its inner end to a pivot head 45 pivoted for radial movement about a pivot pin 46 extending transversely of the related slot 40. Pivot head 45 is flxedly secured to an angular extension 47 which forms a lever or crank arm by which shaft 43 may be swung radially outwardly and inwardly. A cutter 48, of generally cylindrical shape, is mounted for rotation about shaft 43 on a series of longitu dinally spaced antifriction bearings 49, preferably of the roller type as illustrated. A seal 49a seals off the inner end of the bearing race about shaft 43. The outer end of cutter 48 is closed about the end of shaft 43 by an end cutter 50 having an opening 51 therein registering with bore 44 of the shaft and closed by a screw plug 52 which is adapted to be removed to permit introduction of lubricant into the outer end of bore 44. A sealed piston or plunger 53 is slidably mounted in bore 44, the inner end of which communicates through a duct 54 in head 45 with an annular recess 55 about pivot pin 46 (FIG. 6). A duct 56 communicates recess 55 with an axial channel 57in the pivot pin and thence through a duct 58 with the interior of body 16.

The portion of bore 17 of the body which extends between windows 22 and the upper ends of slots 40. defines a cylinder 21 in which is slidably positioned an annular piston 60 having a seal ring 60a mounted in its outer periphery for slidable sealing engagement with the wall of the cylinder. Piston 60 is secured to the upper end of a piston rod 61 having an axial bore 62 which extends downwardly between the several underreamers and projects through an axial opening 63 in the upper end of socket 34 and is slidable therein in response to the axial movements of piston 60. An annular seal ring 64 is disposed in the wall of opening 63 in sealing engagement about the lower end of piston rod 61.

Each of the crank arms 47 of underreamers 42 has its free end secured to a crosshead pin 65 mounted in a crosshead slot 66 fonned in the related side of the exterior of piston rod 61. With this arrangement it will be seen that the movement of piston 60 downwardly will act through crank arms 47 to rotate the underreamers outwardly and upwardly while reverse movement of the piston will act to-retract the underreamers.

A setting sleeve 70 is inserted through the bore of collar 30 and has its upper portion reduced in diameter externally to provide the upwardly facing shoulder 71 adapted to abut shoulder 32 on collar 30. Setting sleeve 70 is initially retained in its uppermost position at which shoulder 71 abuts shoulder 32 by means of shear pins 72 which connect collar 30 to setting sleeve 70. The lower end of the latter is reduced in external diameter to provide a relief recess 73 which is adapted to receive dogs 24 when they are retracted from latching groove 26. The reduction in diameter forms the external downwardly facing beveled shoulder 25 which is adapted to engage an upwardly facing internal shoulder 27 located immediately below windows 22 to limit downward movement of the setting sleeve in body 16 to a position holding dogs 24 in latching engagement in groove 26 (FIG. 2). Relief recess 73 will be disposed in registration with windows 22 and dogs 24 when the setting sleeve is in its uppermost position, as shown in FIG. 1, so that the dogs are free to move inwardly of body 16 out of groove 26.

Piston 60 is linked to the lower end of setting sleeve 70 by a plurality of angularly spaced, elongate-headed bolts 75 (one shown) which screw into the upper end of the piston and extend slidably through perforate ears 76. mounted in the bore of setting sleeve 70 adjacent its lower end. The heads of bolts 75 serve to limit downward movement of piston 60 generally to a distance necessary to fully extend underreamers 42. The bore wall of setting sleeve 70 is provided with an annular groove 77 for engagement by a fishing tool, for purposes to be described subsequently.

A plurality of radially extending nozzles 80 are mounted through the wall of piston rod 61 generally in alignment with the several underreamers 42. These nozzles are positioned so that as piston rod 61 moves downwardly to extend underreamers 42 the nozzles will be positioned below the respective underreamers (FIG. 2) so as to direct fluid discharging therefrom against the wall of well bore W slightly in advance of the underreamers (FIG. 4).

Additional water courses 81 extend longitudinally through the wall of landing shoe 10 to provide communication between the interior of shoe 10 above bit section B and the lower end of shoe 10 so as to direct wash fluid against the extended underreamers to wash cuttings from the cutting surfaces thereof and thereby improve their cutting efficiency.

In operation, the bit section will be inserted into the upper end of easing C and will be allowed to fall by gravity through the bore of the casing until the bit is brought to a stop by the engagement of pins 14 with end walls 19 of spline grooves 18. The parts of the bit section will be positioned as illustrated in FIG. 1 in which the setting sleeve is held in its retracted position by shear pins 72. Latching dogs 24 will thus be free to retract and are effectively retracted into relief recess 73, whereby to allow the free movement of the bit section through the casing and into landing shoe 10.

It will be understood that instead of simply dropping the bit head into the casing and allowing it to fall by gravity to the bottom, it may be lowered on a wire line or other tool string which will be relcasably secured to setting sleeve 70 in a manner and by means well understood by those skilled in the art. If the force of gravity is not sufficient to cause the bit section to fall freely into the landing shoe, it will be understood that by pumping fluid, such as water or drilling mud, into the casing this will act against the restriction formed by the bore of piston rod 61 to provide hydraulic pressure sufficient to drive the bit section downwardly through the casing through any obstructing mud or the like, until it is effectively seated in shoe 10.

When the bit section is in place, downward jarring blows will be applied to the upper end of setting sleeve 70 to break shear pins 72 and move the setting sleeve downwardly so as to force dogs 24 out of recess 73 into groove 26, as seen in FIG.

positions of the parts with the reamers extended and. the ,bit

2. The jarring may beeffected through the coniientionalwire begun to seat the bit section, and as the pressure builds up against therestriction formed by the bore of piston rod 61, a force will be attained sufficient to move piston 60, and piston rod 61 downwardly by the fluid pressure. The downward movement, acting through crosshead pins '65 and crank arms 47 will rotate underreamers 42 outwardly tothe positions shown in FIG. 2. As the underreamers move outwardly and setting sleeve 70 moves' downwardly the exterior portion of the setting sleeve'above relief recess 73 will pass behind dogs 24, and by. reason of the enlarged diameter ofthe sleeve, will force thedogsoutwardly into latching groove'26, thereby effectively anchoring the bit section-to the landingIshbe. The

section latched to'th'c landingishoe isshown in FIG. 2

It will be understood ofeourse', that the casing string will'be. rotated initially to cause pilot bit 38 to initiate drilling ofithe: bore hole and as drilling 'proceeds,;flu'id pressure will be exerted against piston 60 to extend the underreamers which will radially enlarge the bore hole cut by the pilot-bit to a diameter which will allow free passage-of casing stringC so that it will follow directly behind the pilot bit and willeontinuou'sly line the bore hole as drilling proceeds.

The drilling fluid circulation willtion H, swivelS and throughja'conduit in power sub P into, the bore of easing C.;Thence,.through thebit section, the fluid courses 8!. The mud flush will return to, the surface through through hose conned With the underrcamers in their fully'retracted position. as shown in FIG. 3, and dogs 24 also released for retraction into relief recess 73, the'entire bit section can then be pulled out of the casing for repair, replacement or for whatever purpose may be required. If drilling for a desired interval has been completed, withdrawal of the bit section will place the casing in condition for cementing. The'landing shoe may be employed-to receive the usual cementing valve, if desired.

When drilling is to be resumed, the bit section, with the parts in the original retracted positions. will be returned through the bore of the casing to its lodgment in shoe l0. jar- From the foregoing it will be evident that a drilling system is provided in which the casing itself which is ordinarily required to line the bore hole will be used asthe drilling string and will be continuously fed into the hole as the drilling proceeds. thereby obviating all of the additional operations conventionally-required in rotary drilling and for easing the well. The hazards accompanying, the conventional drilling and casing operations, including those arising from round trips" of the drill string, will be obviated, drilling operations greatly facilitated, and time of operation substantially reduced.

It will be understood that various changes and modifications may be made in the details of the illustrative embodiment flowing through the bore of piston 60 and'pistonrod 61 to the I discharge passag'es in thefpilot bit, thenozzles 80 and'wat'er the annulus between well. bore W and casing C: The flow restrictions provided bythe bore ofthe piston rodand the bit passages will assure the maintenance of sufficient hydraulic pressure against the pistonto keep the un'd'erreamers extended By providing the nozzles 80,,"highpressure jets of drilling as long as pumppressure isbeing applied.

fluid will be. directed therefrom radially against the wall ofwell bore W. These jets will function to soften andoften even erode'the earth formations along the bore wall immediately in advance of the underreamers, .and greatly, enhance their amounts sufficient to move pistons 53 to the inner ends of bores 44, after which openings 51 will be closed by means of,

screw plugs 52. When the tool'is in 'operationthe pressure of the drilling fluid will be directed from the interior of the bit body through the several connecting ducts .58, 55, 57, 56 and 54 against plunger 53 in each underreamenarid by its action on the plungers will continuallyforce grease out of bores 44 of the underreamer shafts into the clearance spaces present in the bearing races about bearings 49, thereby keeping the bearings effectively lubricated at all times. I

When necessary to withdraw the bit section from the casing in order to replace or repair the pilot bit, underreamers or any other part of the bit section, a fishing too, designated generally by the letter T, of any generally conventional form, the details of which do not form a part of this invention, will be run into the casing bore on a wire line, or tubing string if desired, and will be latched into groove 77 of the setting sleeve. On application of upward pull to the fishing string, the setting sleeve will be drawn upwardly to place relief recess 73 opposite dogs 24 which will thereby be freed to retract sufficiently to release the bit section from landing shoe l0. Underreamers 42 will swing inwardly of their own weight as soon as pump pressure b. cooperating'means within the scope of the appended claims but without departing from the spirit of this invention.

l claim:

.1 Apparatus for rotary drilling of wells using casing as the I drill pipe, comprising in combination with a string of casing and means for rotating the same;

' a. abit section bodily insertable and removable through the on'the' bits'ection' and'thc lower end portion of the casing for landing the bit section in said lower end portion in nonrotat ive relation to the casing;

c. said bit section comprising:

i. a-generally tubular body; v

ii. radially mova'ble anchor means mounted on the body for releasably anchoring the body to the casing;

iii. a pilot bit carried by the lower end of the body;

iv. a plurality of angularly spaced'underreamers mounted on the body for radial movement between extended positions for enlarging the diameter of the bore hole made by the pilot bit and positions fully within the perimeter of said body;

piston means operablyconnected to said undrreamers and reciprocable in the bore of the body between upper and lower positions respectively retracting and extending said underreamers;

vi. sleeve means in said body reciprocable between upper and lower positions respectively releasing and actuating said anchor means; and viijmeans initially securing said sleeve means to' said'body in said upper position and releasable for movement to said lower position in response to jarring action .to actuate said anchor means; and means operable in response to fluid pressure applied to the piston means through the casing string to extend said underreamers.

2. The apparatus according to claim 1 including means operably connecting the piston means to each of the underreamers comprising:

a. a crank arm angularly secured to the underreamer; and

b. crosshead pin-and-slot connections between the free end of the crank arm and the piston means. 3. The apparatus according to claim 1 wherein said initial securing means comprise shear pins.

4. The apparatus according to claim .1 wherein said sleeve means includes means adapted for engagement by a fishing tool to apply upward pull to the sleeve means.

5. The apparatus according to claim 1 wherein said piston means includes:

- a. a'downwardly extending hollow piston rod; and

b. a plurality of radially directed nozzles through the wall of said rod located to direct fluid pressure applied to said piston means radially toward the well wall at points in advance of the extended underreamers.

6. The apparatus according to claim 1 wherein each of said underreamers comprises:

a. a shaft having an axial bore adapted to be filled with lubricant;

b. a generally cylindrical cutter body having a closed outer end rotatably disposed about said shaft;

c. antifriction bearings between the shaft and the cutter body;

d. plunger means slidably disposed in said bore in compressive engagement with the body of lubricant therein; and

e. duct means in the underreamer arranged to direct pressure fluid from the interior of the bit section against said plunger means whereby to force lubricant out of said bore and about said bearings.

7. Apparatus according to claim 1 including nozzle means carried by said body for directing pressure fluid radially from the body against the well wall at points closely in advance of the extended underreamers.

8. The apparatus according to claim 1 wherein said cooperating means includes:

a. a tubular landing shoe secured to the lower end of the casing string;

b. inwardly projecting splines in the bore ofthe shoe; and

c. spline grooves in the bit body open at their lower ends for receiving the splines in response to relative downward movement of the bit body.

9. The apparatus according to claim 2 wherein said anchor means includes:

a. a plurality of angularly spaced latching dogs disposed in openings in the wall of said body; and

b. an annular latching groove in the wall ofsaid landing shoe arranged for latching engagement with said dogs.

10. The apparatus according to claim 8 wherein said sleeve means includes an annular relief recess about its exterior which is registrable with said latching dogs when said Is sleeve means is in said upper position to permit retraction of said latching dogs from said latching groove.

11. The apparatus according to claim 2 including a plurality of flow passages extending longitudinally through the wall of said landing shoe between interior points above said hit section to exterior points above the underreamers. 

1. Apparatus for rotary drilling of wells using casing as the drill pipe, comprising in combination with a string of casing and means for rotating the same; a. a bit section bodily insertable and removable through the bore of the b. cooperating means on the bit section and the lower enD portion of the casing for landing the bit section in said lower end portion in nonrotative relation to the casing; c. said bit section comprising: i. a generally tubular body; ii. radially movable anchor means mounted on the body for releasably anchoring the body to the casing; iii. a pilot bit carried by the lower end of the body; iv. a plurality of angularly spaced underreamers mounted on the body for radial movement between extended positions for enlarging the diameter of the bore hole made by the pilot bit and positions fully within the perimeter of said body; v. piston means operably connected to said undrreamers and reciprocable in the bore of the body between upper and lower positions respectively retracting and extending said underreamers; vi. sleeve means in said body reciprocable between upper and lower positions respectively releasing and actuating said anchor means; and vii. means initially securing said sleeve means to said body in said upper position and releasable for movement to said lower position in response to jarring action to actuate said anchor means; and means operable in response to fluid pressure applied to the piston means through the casing string to extend said underreamers.
 2. The apparatus according to claim 1 including means operably connecting the piston means to each of the underreamers comprising: a. a crank arm angularly secured to the underreamer; and b. crosshead pin-and-slot connections between the free end of the crank arm and the piston means.
 3. The apparatus according to claim 1 wherein said initial securing means comprise shear pins.
 4. The apparatus according to claim 1 wherein said sleeve means includes means adapted for engagement by a fishing tool to apply upward pull to the sleeve means.
 5. The apparatus according to claim 1 wherein said piston means includes: a. a downwardly extending hollow piston rod; and b. a plurality of radially directed nozzles through the wall of said rod located to direct fluid pressure applied to said piston means radially toward the well wall at points in advance of the extended underreamers.
 6. The apparatus according to claim 1 wherein each of said underreamers comprises: a. a shaft having an axial bore adapted to be filled with lubricant; b. a generally cylindrical cutter body having a closed outer end rotatably disposed about said shaft; c. antifriction bearings between the shaft and the cutter body; d. plunger means slidably disposed in said bore in compressive engagement with the body of lubricant therein; and e. duct means in the underreamer arranged to direct pressure fluid from the interior of the bit section against said plunger means whereby to force lubricant out of said bore and about said bearings.
 7. Apparatus according to claim 1 including nozzle means carried by said body for directing pressure fluid radially from the body against the well wall at points closely in advance of the extended underreamers.
 8. The apparatus according to claim 1 wherein said cooperating means includes: a. a tubular landing shoe secured to the lower end of the casing string; b. inwardly projecting splines in the bore of the shoe; and c. spline grooves in the bit body open at their lower ends for receiving the splines in response to relative downward movement of the bit body.
 9. The apparatus according to claim 2 wherein said anchor means includes: a. a plurality of angularly spaced latching dogs disposed in openings in the wall of said body; and b. an annular latching groove in the wall of said landing shoe arranged for latching engagement with said dogs.
 10. The apparatus according to claim 8 wherein said sleeve means includes an annular relief recess about its exterior which is registrable with said latching dogs when said ls sleeve means is in said upper position to permit retraction of said latching dogs from said latching groove.
 11. The apparatus accordIng to claim 2 including a plurality of flow passages extending longitudinally through the wall of said landing shoe between interior points above said bit section to exterior points above the underreamers. 